April 20 (Bloomberg) -- Channeling the nation’s relief,
President Barack Obama said the capture of the surviving Boston
Marathon bombing suspect capped an “important chapter of this
tragedy” while spurring a search into the motives and potential
terrorist links behind the blasts.

“All in all, this has been a tough week, but we’ve seen
the character of our country once more,” Obama said at the
White House in a nighttime statement after a day of staying
publicly silent as an almost 24-hour manhunt unfolded.

The capture yesterday of Dzhokar Tsarnaev in Watertown,
Massachusetts, shortly before the president spoke left “many
unanswered questions,” Obama said. While cautioning against a
“rush to judgment,” he said the investigation will seek to
find out why two young men who studied in the U.S. would turn to
such violence.

“The families of those killed so senselessly deserve
answers,” Obama said, as do “the wounded -- some of whom now
have to learn how to stand and walk and live again.”

Tsarnaev, 19, was taken into custody following a manhunt
that paralyzed Boston and its suburbs for much of the day. His
older brother, Tamerlan, 26, died in a confrontation with police
in Watertown the previous night after the shooting death of a
Massachusetts Institute of Technology campus officer. The
brothers had been pursued as the suspects in the April 15
bombings that killed three people and injured more than 170.

FBI Briefing

“Whatever hateful agenda drove these men to such heinous
acts will not -- cannot -- prevail,” Obama said. “Whatever
they thought they could ultimately achieve, they’ve already
failed.”

The president learned of the capture while watching
television in the White House residential area, then went to the
Oval Office, where he received a briefing call from FBI Director
Robert Mueller.

U.S. House Speaker John Boehner said “the thanks of a
grateful nation” was going to “every single federal, state,
and local law enforcement official who went above and beyond to
apprehend” the younger Tsarnaev.

“It was a job well done under trying circumstances, to say
the least,” the Ohio Republican said in a statement from
Washington.

Senate Minority Leader Mitch McConnell, a Kentucky
Republican, said in a statement from Louisville that, “We have
marveled at the coordination, skill, and bravery of military,
intelligence, and law enforcement officials at every level --
from federal agents to suburban beat cops to the campus police
officer at MIT who gave his life in the line of duty.”

Texas Explosion

Last night’s capture culminated an extraordinary week of
anxiety and rapid-fire developments that began with the bombings
near the marathon’s finish line and ended with Tsarnaev found
hiding in a boat in a suburban backyard.

In between, the discovery of ricin-laced letters sent to
officials in Washington -- including Obama -- set the nation’s
capital on edge, and the small town of West, Texas, suffered
devastation with an April 17 fertilizer-plant explosion that
killed at least 14 people and injured at least 200.

Obama mentioned that blast during his White House statement
and moments later declared a state of emergency in Texas,
granting federal aid to supplement state and local resources.

Even as congressional leaders joined Obama in responding
with elation and praise for law enforcement following Tsarnaev’s
capture, the potential political ripple effects of the Boston
bombings for his presidency and legislative agenda began to
reverberate.

Prosecuting Tsarnaev

Lawmakers said they would turn a fresh focus to combating
homegrown terrorism in the days to come, raised questions about
how the interrogation and prosecution of Tsarnaev should be
handled, and signaled a more difficult road ahead for Obama’s
push to rewrite U.S. immigration laws.

The Tsarnaev brothers, who lived in Cambridge, came to the
U.S. from the former Soviet Union about a decade ago. They are
ethnic Chechens whose father lives in Russia.

Lawmakers warned that the Boston bombings indicated the
potency of the threat of homegrown terrorism, vowing to
scrutinize it for clues on how to prevent future such events.

“While we have made it more difficult for terrorists to
carry out attacks from overseas, the attack on the Boston
Marathon is indicative of the shift in terrorists’ tactics in
recent years to inspire people who are living in the United
States to strike,” said Republican Representative Michael
McCaul of Texas, chairman of the House Homeland Security
Committee. “While several plots of this nature have been
thwarted, this is the first to succeed.”

Pending Questions

McCaul said his panel would ask in the coming weeks “how
this happened, and how we can prevent it from happening again.”

Throughout the hunt, Obama and Vice President Joe Biden
received regular briefings from top officials in Washington and
Boston. The president spoke on the phone yesterday with Russian
President Vladimir Putin about the investigation.

Earlier in the day, Putin’s spokesman Dmitry Peskov said
Russia had been “very attentively watching” the developments.

U.S. authorities haven’t yet found evidence that the
suspects were connected to other individuals or groups,
according to a person briefed on the investigation who asked not
to be identified to discuss the probe.

The saga demonstrates the pressing need for U.S. law
enforcement to maintain robust intelligence and counterterrorism
programs at the state and local levels, said Republican
Representative Peter King of New York.

Islamist ‘Threat’

“The fact that these terrorists were from overseas, living
legally in our country for a period of time, and the fact that
there was no federal intelligence or chatter prior to the
marathon bombings demonstrates once again the Islamist terrorist
threat to our country from within our borders,” said King, the
chairman of the Homeland Security panel that oversees
counterterrorism and intelligence.

“As has been demonstrated in recent years there is a
significant terrorist threat from people living within our
country under the radar screen,” he said.

King, along with Republican Senators John McCain of
Arizona, Lindsey Graham of South Carolina and Kelly Ayotte of
New Hampshire, released a joint statement today encouraging the
Obama administration to treat Tsarnaev as a “potential enemy
combatant,” depriving him of the rights given U.S. law
enforcement suspects in custody, in order to learn more about
possible future attacks.

48 Hours

“We have concerns that limiting this investigation to 48
hours, and exclusively relying on the public safety exception to
Miranda, could very well be a national security mistake,” they
wrote in a statement. “It could severely limit our ability to
gather critical information about future attacks from this
suspect.”

The Obama administration has not classified Tsarnaev, a
U.S. citizen, as an enemy combatant. However, they’ve also opted
against reading him the Miranda warning that gives suspects a
chance to consult a lawyer before answering questions, according
to a Justice Department official.

The administration invoked a public-safety exception that
lets law enforcement conduct limited questioning and allows the
introduction of statements from those interviews into evidence
before reading him the Miranda warning that gives suspects a
chance to consult a lawyer before answering questions, said the
official, who asked not to be identified because the move wasn’t
announced.

Immigration Issue

Some critics of a far-reaching bipartisan effort to revamp
U.S. immigration laws hinted that the Boston case could
complicate the push.

“Given the events of this week, it is important for us to
understand the gaps and loopholes in our immigration system,”
said Republican Senator Charles Grassley of Iowa, who has
opposed previous efforts to offer legal status to undocumented
immigrants living in the U.S., as the measure would do.

“While we don’t yet know the immigration status of people
who have terrorized the communities of Massachusetts,” Grassley
said at a hearing on Capitol Hill, it could “shed light on the
weaknesses of our system.”

Tamerlan Tsarnaev was a legal resident of the U.S. while
his brother, Dzhokar Tsarnaev, became a naturalized citizen on
Sept. 11, 2012, according to a government official briefed on
the matter who asked not to be identified because the
investigation was in progress.

Democratic proponents of the immigration measure urged
lawmakers not to allow the situation in Boston to derail it.
People shouldn’t “jump to conclusions” and “conflate” the
events in Boston with the immigration rewrite proposal, said
Senator Charles Schumer of New York.